Normal
There is a large variety of trash mobs inside Hellfire Ramparts. Most pulls will be a minimum of three, and range up to six. Crowd control is extremely important in this instance, with a Mage being preferred. Rogues trying to crowd control will have difficulty in some areas, as there are a lot of wolves who can see through stealth. Warlocks can Seduce and Priests can Mind Control, as most of the mobs are humanoids, but this isn't the preferred method.
Pulls need to be made carefully, especially if the levels of the group are on the low end. Every member of the party will have to be on top of every aspect, as things can go wrong very quickly. An alternative to a lot of crowd control would be a Paladin AoE-tanking, but this method isn't recommended without a very strong healer and tank.
Heroic
Trash is virtually unchanged on heroic mode. Of course, mobs hit much harder, as they do in all heroics. Crowd control becomes even more important than on normal mode, as one mistake can easily lead to a wipe. Pulls must be made very carefully, watching out for patrols and additional groups.